08-05-2015, 04:21 PM
Under water welding is the installation of large patches, as well as the attachment of suitable pad-eyes presents a more complicated problem to the diver than does underwater cutting. Considerable practice is necessary to achieve a consistently good standard of underwater welding for salvage work. As a result, the diver’s underwater welding techniques must conform to acceptable standards. Also, the ocean acts as a large heat sink and draws off the heat of the electrode. This may cause blow holes and possible loss of strength between the patch and hull. This is true because the gas cannot escape from the molten pool of metal due to sudden cooling by the surrounding water. Despite the above shortfalls, underwater welds of good strength that are acceptable for salvage work are possible. Unless otherwise specified, the term “underwater welding” as used in this manual refers to the wet welding technique where no mechanical barrier separates the welding arc from the surrounding water.